Performance of Sand Filtration System with Different Sand Bed Depth for Polishing Wastewater Treatment

Abstract

Sand filtration is a polishing type of treatment system that is widely used as an efficient, cost-effective and simple treatment method. The efficiency of sand filtration relies mainly on the capacity of sand bed depth. Different sand bed depth affects the filtration rate and the contaminant removal differently. Hence, this study aims to investigate the effect of different sand media depth on the removal efficiency of the filtration process. An experimental sand filter with three design modifications of different sand bed depth, 30 cm, 60 cm, and 90 cm, was operated as polishing stage of an effluent from conventional activated sludge process. The highest filtration rate was recorded using sand depth of 30 cm. Higher filter bed depth result in lower filter rate which result in smaller filtrate volume. Highest E. Coli and COD removal, are 95.5% and 52.2%, respectively, recorded using 30 cm sand depth. Meanwhile, highest TSS and turbidity removal are 91.0% and 77.3%, respectively, with sand depth of 90 cm. Highest total coliform and BOD removal are 88.3% and 68.0% respectively by using sand depth of 60 cm. This study demonstrated that the sand filter is more efficient in removing suspended contaminants and coliforms compared to removing dissolved contaminants.